The Internet has created a whole new world for ad agencies, but not for the actors who star in their commercials.

Technology has forced the ad business to adapt to different media to deliver their message.

But the system for paying commercial actors has remained pretty much the same.

For instance, actors get a standard fee for ads that appear on TV and then move to the Web, but they are not guaranteed the same rates for Web-only ads, an issue of concern as advertisers turn increasingly to the Internet.

This weekend, Madison Avenue will meet with the two biggest entertainment unions, the Screen Actors Guild and the American Federation of Television and Radio Artists, to start hashing out these issues.

But first the unions and a coalition of advertisers and agencies will hire an outside consultant to come up with proposals for a system that takes into account the Web, cellphones, iPods and other ways of delivering advertising, said Douglas Wood, the chief negotiator for the ad industry.

The current contract expires Oct. 29, although both sides have indicated that could be extended.